Evidence for the Production of Prompt Like-Sign Dimuon Events by High-Energy Neutrinos

We report the observation of 46 ${\mu }^{-}{\mu }^{-}$ events in high-energy neutrino-nucleon collisions at Fermilab. Measurement of the production rate of the ${\mu }^{-}{\mu }^{-}$ events relative to that of ${\mu }^{-}{\mu }^{+}$ events in targets of different hadronic absorption lengths give $\frac{N^{\mathrm{prompt}}\left({\mu }^{-}{\mu }^{-}\right)}{N^{\mathrm{prompt}}\left({\mu }^{-}{\mu }^{+}\right)}=0.06\mathrm{}\pm 0.05$ for $p_{\mu }>5\mathrm{}$ GeV/c, and 0.12±0.05 for $p_{\mu }>10\mathrm{}$ GeV/c. The properties and possible origins of these events are discussed.